Add a TPM signature verifier example

[tomoveu]

This is a good first issue for someone who wants to get into OSS/TPM development.

We need a simple example to show TPM signature verification.

We already have examples for TPM2_Quote and TPM2_GetTime that can be used to generate signed TPM blob(data).

Details:

• Both TPM2_Quote and TPM2_GetTime produce similar output using TPM2B_ATTEST and TPMT_SIGNATURE structures.
• The TPMT_SIGNATURE holds the TPM generated signature over the data in TPM2B_ATTEST.